DETAILED DESCRIPTION OF THE INVENTION

[0009] While the present invention will be described fully hereinafter with reference to the accompanying drawings, in which a particular embodiment is shown, it is understood at the outset that persons skilled in the art may modify the invention herein described while still achieving the desired result of this invention. Accordingly, the description which follows is to be understood as a broad informative disclosure directed to persons skilled in the appropriate arts and not as limitations of the present invention.

[0010] A preferred embodiment of a swivel arm adjustment 10 of the present invention is shown in FIG. 1 attached to a chair 12. The swivel arm adjustment 10 is adapted to be fastened to a sleeve 14 which covers an arm 15 of the chair 12 such as an office or other style of chair, and to an armrest 16. The swivel arm adjustment device 10 allows the user to pivot the armrest 16 in various positions to increase comfort and reduce fatigue.

[0011] The swivel arm adjustment 10 is rectangular in shape and includes a top member 18 and a base member 20. The top member 18, as shown in FIGS. 2 and 3, includes a centralized aperture 22 a first arcuate slot 24 and a second arcuate slot 28. The top member 18 is a generally planar with a top surface 30, best shown in FIG. 2, and a spaced apart bottom surface 32, best shown in FIG. 3. The top surface 30 has a recessed center portion 34 and two raised end portions 36 and 37. The top surface 30 also includes two apertures 39 and 41 to allow access to the hardware on the base member 20. The two raised end portions 36 and 37 come in contact with and support the armrest 16 upon assembly. The recessed center portion 34 houses the centralized aperture 22 and the first and second arcuate slots 24 and 28. The recessed center portion 34 is reinforced by a rib 38 that extends from the centralized aperture 22 to end portions 36. The raised end portions 36 and 37, shown in FIG. 1, are planar and include apertures 40 and 42 to allow for the passage of fasteners 44 used to fasten the armrest 16 to the swivel arm adjustment 10.

[0012] The centralized aperture 22, as shown in FIG. 2, is ringlike in shape and extends upwardly from the recessed center portion 34. The top edge 46 of the aperture 22 is at an elevation slightly higher than the raised end portions 36 and 37. Outer circumference 48 is in contact with inside surface 50 of side walls 52 of the recessed center portion 34. The outer circumference 48 is also in contact with outside surface 54 of the first arcuate slot 24, opposite the resistance grooves 26. Inner surface 56 of the centralized aperture has a flat surface that acts as a bushing housing when the swivel arm adjustment system 10 is assembled. The inner surface 56 further includes an annular ridge 58 located near the bottom edge 60 which acts as a retaining ring to prevent detachment once the base member 20 is installed.

[0013] The wall surrounding the first arcuate slot 24, shown best in FIG. 2, is elevated above the recessed center portion 34 and includes a first side 64 and a second side 66. An inside surface 62 of the first side 64 is smooth to allow a detent pin 68 formed on the base member 20 to slide along the surface without resistance. The second side 66 of the inside surface 62 contains five resistance grooves 26 placed along the entire length of the side 66. The number of resistance grooves 26 can be varied depending on the number of adjustment positions desired. The resistance grooves 26 are arranged so that one of the grooves 26 has its centerline positioned midway along the length of the first arcuate slot 24. The four remaining resistance grooves 26 are paired on both sides of the center groove 26 creating a center detent position, two right detent positions and two left detent positions. The outer two resistance grooves 26 define edges 72 of the slot 24 preventing any further movement. The detent pin 68 is sized so that when it is inserted into the first arcuate slot 24 the outer circumference 70 is in contact with the inside surface 62 of the first side 64 and one of the resistance grooves 26, resisting any movement. Adjacent to the first arcuate slot 24 is a second arcuate slot 28 which is created by an absence of material on the bottom surface 32. The second arcuate slot 28 follows the curve of the outside surface 54 and wraps around the edges 72. The purpose of the second slot 28 is to provide space to allow for the encroachment of the second side 66 of the first arcuate slot 24. The outside surface 54 of the second side 66 is uninhibited by any structure allowing the second side 66 to bow outward when enough force is exerted by the detent pin 68, allowing the pin 68 to proceed to the next resistence groove 26. The pin 68 is moved by applying enough rotational force to the top member 18 causing it to move.

[0014] The bottom surface 32, as shown in FIG. 3, is generally planar with the exception of two depressions 74 located at the extremities of the surface 32. The bottom surfaces 76 of the depressions 74 house the apertures 40 and 42, visible from the top surface 30. The depressions 74, shown best in FIG. 3, are designed to receive the head of a screw or other fastener 44, shown in FIG. 1 as a bolt, to be recessed below the surface 32. The ability to recess the fasteners 44 is important to allow the center section 82 of the bottom surface 32 to pivot in relation to the base member 20. The center section 82, shown in FIG. 3, also includes the centralized aperture 22, the first arcuate slot 24 with resistance grooves 26 and the second arcuate slot 28. The centralized aperture 22, the first arcuate slot 24 with resistance grooves 26 and the second arcuate slot 28 are flush with a center section 82 of the bottom surface 32. The top member 18 is designed so that the entire structure can be made out of a single piece of material. While it is preferable to form the entire top member 18 out of injected molded plastic, it is also possible to construct the member 18 out of metals, resins or other materials. To aid in the pivot action of the top member 18, a plastic containing a self-lubricating additive such as graphite may be used.

[0015] The base member 20, of the swivel arm adjustment 10, as shown in FIGS. 4 and 5, includes a top surface 84 and a spaced apart bottom surface 86. The base member further includes four edges 87, 88, 89, 90. The top surface 84 is generally planar and includes a central bushing 92 and detent pin 68 which extend from the surface 84. The top surface 84 further includes two apertures 94 and 95 and two notches 96. The central bushing 92 is circular in shape and has an inner surface 98 and an outer surface 100. The outer surface 100 includes an integrated annular snap-ring 102 located near the top edge 104 of the central bushing 92. The snap-ring 102 incorporates a beveled upper edge 106 designed to allow the bushing 92 to be pressed into the aperture 22 on the top member 18, snapping them together. The lower edge 108 forms a ledge, preventing disassembly by interlocking with the top surface 59 of the annular ridge 58. When the bushing 92 is pressed into the centralized aperture 22 the pressure exerted by the snap-ring 102 against the annular ridge 58 causes the walls 91 of the bushing 92 to constrict and the walls of the aperture 22 to expand, allowing the snap-ring 102 to pass by the annular ridge 58 and expand outwardly locking the two members together. The diameter of the snap-ring 102 is sized so that it is in contact with inner surface 56 of the aperture 22. While the fit between the aperture 22 and the bushing 92 involves surface contact, it is noted that the two elements are sized to allow pivotal rotation of the top member 18 with respect to the base member 20. The detent pin 68 is cylindrical in shape and affixed to the top surface 84 along the center line of the length of the base member 20. The detent pin 68 has been positioned so that when the base member 20 and the top member 18 are aligned and pressed together, the detent pin 68 slides into the center resistance groove 26 of the first arcuate slot 24. The apertures 94 and 95 are oriented in a staggered configuration, diagonal from the other. The apertures 94 and 95 further include a stepped bore 110, shown best in FIG. 4, to allow the head of a fastener 112, shown in FIG. 1, to be recessed below the top surface 84. Apertures 94 and 95 allow the use of fasteners 112 to attach the swivel arm adjustment 10 to the sleeve 14 of the chair 12. The top surface 84 of the base member 20 is in slidable contact with the bottom surface 32 of the top member 18 upon assembly. The notches 96 on the base member 20 are placed at opposing ends along edges 87 and 89. The notches 96 are designed to allow the fasteners 44 to be removed and installed from the armrest 16, shown in FIG. 1, when the chair 12 is either assembled or disassembled. The bottom surface 86, as shown in FIG. 5, includes a plurality of ribs 114 in order to add flexural strength to the base member 20. The base member 20 along with the central bushing 92 and detent pin 68, in the preferred embodiment, are formed in a unitized fashion out of a single piece of material. While it is preferred to form the base member 20 from plastic, other materials such as metal or resin can be used, as well as various methods of manufacture such as injection molding and casting. Also, lubricants can be added to the plastic or metal to aid in the pivotal movement of the swivel arm adjustment 10.

[0016] During the assembly of office chair 12, shown in FIG. 1, at the factory incorporating the swivel arm adjustment 10, the top member 18 is attached to the armrest 16 by inserting the top surface 30 into the inside hollow of the armrest 16 and fastening the top member 18 and the armrest 16 together with screws 44. Similarly, the bottom member 20 is placed upon the top of the sleeve 14 and fastened to the sleeve 14 with the use of screws 112. Once the members are properly fastened, the aperture 22 of the top member 18 and the bushing 92 of the base member 20 are aligned and a force is exerted to snap the two members together. Once attached, a pivotal connection is formed and cannot be easily disassembled. The swivel arm adjustment 10 allows the armrest 16 of a chair to pivot either clockwise or counterclockwise through a predetermined number of positions without the use of tools, reducing the time required for assembly.

[0017] Various features of the invention have been particularly shown and described in connection with the illustrated embodiment of the invention, however, it must be understood that these particular arrangements merely illustrate, and that the invention is to be given its fullest interpretation within the terms of the appended claims.